U.S. FDA Grants Orphan Drug Designation to ONESTX’s Lead Candidate LON-21 for the Treatment of Huntington’s Disease
Olavide Neuron STX S.L. (ONESTX), a clinical-stage biotechnology company pioneering therapies based on the biology of aging and neurosteroid modulation, today announced that the U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation (ODD) to its lead investigational drug, LON-21 (STX64/Irosustat), for the treatment of Huntington’s Disease (HD).
Huntington’s disease is a rare, inherited, and ultimately fatal neurodegenerative disorder that causes the progressive breakdown of nerve cells in the brain, leading to severe motor, cognitive, and psychiatric symptoms. Currently, there are no approved disease-modifying treatments capable of halting or reversing the progression of the disease.
LON-21 is a first-in-class, orally administered, irreversible Steroid Sulfatase (STS) inhibitor. By selectively inhibiting STS, LON-21 is designed to restore the endogenous balance of sulfated neurosteroids (such as the DHEAS/DHEA and PREGS/PREG ratios) in the brain. Preclinical studies have demonstrated that this mechanism yields pleiotropic neuroprotective effects, including the reduction of proteotoxic aggregation, mitigation of neuroinflammation, and restoration of synaptic plasticity and memory. Furthermore, LON-21 leverages a highly de-risked profile, having already demonstrated excellent human safety and tolerability in previous Phase I/II clinical trials for other indications.
“Receiving Orphan Drug Designation from the FDA is a significant regulatory milestone for ONESTX and an important step forward for the Huntington’s disease community” said Dr. Ángel Cebolla, Chief Executive Officer of ONESTX.
“This designation not only validates the strong scientific rationale behind our neurosteroid-targeting approach but also provides a clear, accelerated pathway to bring this potentially transformative therapy to patients. For our company, it fundamentally strengthens our strategic positioning as we enter our next phase of clinical development.”
The FDA’s Orphan Drug Designation program provides orphan status to drugs defined as those intended for the safe and effective treatment, diagnosis, or prevention of rare diseases that affect fewer than 200,000 people in the United States. The designation provides ONESTX with several significant benefits, including exemption from FDA user fees, assistance with clinical trial design, and the potential for seven years of market exclusivity upon regulatory approval.
Advancing to Phase IIa Clinical Trials Supported by this regulatory milestone, ONESTX is currently finalizing a €7 million Series A financing round. The proceeds will be directly allocated to launching a multicenter Phase IIa proof-of-concept clinical trial for LON-21 in patients with early to moderate Huntington’s Disease.
Success in this orphan indication will also serve to further de-risk the company’s broader pipeline, which includes advancing the clinical development of LON-21 as a treatment for Alzheimer’s disease and other age-related cognitive disorders.
About ONESTX: Olavide Neuron STX S.L. (ONESTX) is a Spanish biotechnology company dedicated to «Saving Memories» by developing disease-modifying therapies for neurodegenerative conditions. Founded as a spin-off from the Universidad Pablo de Olavide (Seville) and backed by experienced biotech investors and international advisors, ONESTX focuses on restoring brain neuroprotection by targeting the steroid sulfation/desulfation axis.
For more information, please visit www.onestx.bio.
